Three-terminal vertical cavity surface emitting laser (VCSEL) and a method for operating a three-terminal VCSEL
View Patent ↗A three-terminal VCSEL is provided that has a reduced fall time that allows the VCSEL to be operated at higher speeds. Methods of operating the three-terminal VCSEL are also provided. The VCSEL can be operated at higher speeds without decreasing the optical output of the VCSEL when it is in the logical HIGH state.
1. A three-terminal vertical cavity surface emitting laser (VCSEL) comprising:
a substrate having at least a top surface and a bottom surface;
an emitter contact corresponding to a first terminal;
a first plurality of n-type layers disposed on top of the top surface of the substrate, wherein the first plurality of n-type layers comprise pairs of layers of alternating high and low refractive index that operate as a first distributed Bragg reflector (DBR);
at least one n-type cavity confining layer disposed on top of the first plurality of n-type layers;
a plurality of active layers containing one or more quantum wells disposed on top of the n-type cavity confining layer, the active layers comprising a light-emitting material and being either lightly p-doped or intrinsic;
at least one p-type cavity confining layer disposed on top of the plurality of active layers;
a base contact disposed on or in a portion of the p-type cavity confining layer such that the base contact is in contact with at least one of the active layers, the base contact corresponding to a second terminal of the VCSEL;
a second plurality of n-type layers disposed on top of a portion of the p-type cavity confining layer, wherein the second plurality of n-type layers comprise pairs of layers of alternating high and low refractive index that operate as a reflector; and
a collector contact disposed on or in a portion of at least one of the second plurality of n-type layers such that the collector contact is in contact with at least one of the n-type layers of the second plurality, and wherein the collector contact corresponds to a third terminal of the VCSEL.
2. The VCSEL of claim 1 , wherein the substrate is an n-type substrate.
3. The VCSEL of claim 1 , wherein the substrate is a semi-insulating substrate.
4. The VCSEL of claim 1 , wherein the pairs of layers of the second plurality of n-type layers comprise a second DBR.
5. The VCSEL of claim 4 , wherein at least some of the layers of the second DBR that have high indexes of refraction include quantum wells.
6. The VCSEL of claim 5 , further comprising an n-type collector contact layer disposed between said at least one p-type cavity confining layer and the second DBR, and wherein the collector contact is disposed on or in the n-type collector contact layer.
7. The VCSEL of claim 1 , wherein the pairs of layers of the second plurality of n-type layers comprise a dielectric mirror.
8. The VCSEL of claim 7 , further comprising:
an n-type collector contact layer disposed between said at least one p-type cavity confining layer and the dielectric mirror, and wherein the collector contact is disposed on or in the n-type collector contact layer.
9. The VCSEL of claim 1 , further comprising an interconnect that connects the base contact to the collector contact.
10. A three-terminal vertical cavity surface emitting laser (VCSEL) comprising:
a substrate having at least a top surface and a bottom surface;
an emitter contact corresponding to a first terminal;
a first plurality of p-type layers disposed on top of the top surface of the substrate, wherein the first plurality of p-type layers comprise pairs of layers of alternating high and low refractive index that operate as a first distributed Bragg reflector (DBR);
at least one p-type cavity confining layer disposed on top of the first plurality of p-type layers;
a plurality of active layers containing one or more quantum wells disposed on top of the p-type cavity confining layer, the active layers comprising a light-emitting material and being either lightly n-doped or intrinsic;
at least one n-type cavity confining layer disposed on top of the plurality of active layers;
a base contact disposed on or in a portion of the n-type cavity confining layer such that the base contact is in contact with at least one of the active layers, the base contact corresponding to a second terminal of the VCSEL;
a second plurality of p-type layers disposed on top of a portion of the n-type cavity confining layer, wherein the second plurality of p-type layers comprise pairs of layers of alternating high and low refractive index that operate as a reflector; and
a collector contact disposed on or in a portion of at least one of the second plurality of p-type layers such that the collector contact is in contact with at least one of the p-type layers, the collector contact corresponding to a third terminal of the VCSEL.
11. The VCSEL of claim 10 , wherein the substrate is a p-type substrate.
12. The VCSEL of claim 10 , wherein the substrate is a semi-insulating substrate.
13. The VCSEL of claim 10 , wherein the pairs of layers of the second plurality of p-type layers comprise a second DBR.
14. The VCSEL of claim 13 , wherein at least some of the layers of the second DBR that have high indexes of refraction include quantum wells.
15. The VCSEL of claim 13 , further comprising a p-type collector contact layer disposed between said at least one n-type cavity confining layer and the second DBR, and wherein the collector contact is disposed on or in the p-type collector contact layer.
16. The VCSEL of claim 10 , wherein the pairs of layers of the second plurality of p-type layers comprise a dielectric mirror.
17. The VCSEL of claim 16 , further comprising:
a p-type collector contact layer disposed between said at least one n-type cavity confining layer and the dielectric mirror, and wherein the collector contact is disposed on or in the p-type collector contact layer.
18. The VCSEL of claim 10 , further comprising an interconnect that connects the base contact to the collector contact.